# RTC_SetAlarmParamAsync

## C Specification

      #include <nitro/rtc.h>

      RTCResult RTC_SetAlarmParamAsync(
                  RTCAlarmChan            chan,
                  const RTCAlarmParam*    param,
                  RTCCallback             callback,
                  void*                   arg );

## Description

Asynchronously writes alarm interrupt parameter values to the real time clock.

This function sends alarm interrupt data to ARM7 and returns the process result without waiting for a response from the processor.

To get the actual process result from the processor, you must use the `result` argument that is passed to the user callback function.

If this function fails, no operation is performed and no user callback function is called.

## Cautions

Do not define parameter values of nonexistent days of the week or times.

Values are set to the RTC as specified by the `param` argument asynchronously with respect to the function. Do not use this variable for anything else until a user callback function confirms the completion of this asynchronous operation.

Unless the RTC alarm interrupt permission status is `permit`, it is not possible to write parameter values to the real time clock, causing any attempted call of this function to fail.

## Arguments

`chan` | Uses `RTCAlarmChan` to specify an alarm channel.
`param` | Pointer to `RTCAlarmParam` containing parameters to set
`callback` | Pointer to specific `RTCCallback` function to be used
`arg` | Argument to be passed to a callback function

## Return Values

If the request succeeds, it returns 0.
If the request fails, it returns some numeric value other than 0.

## See Also

`RTC_SetAlarmParam`, `RTC_GetAlarmParam`, `RTC_GetAlarmParamAsync`, `RTCResult`, `RTCAlarmChan`, `RTCAlarmParam`, `RTCCallback`

## Revision History

05/18/2004 Initial Version